Presence of the ion zinc in the cochlear nuclei
Abstract
The chemical element zinc has been in the last decades strongly studied. It is well known that it is present in some different structures of the Central Nervous System, acting as a co-factor of excitatory glutamatergic synapsis. Its function is not yet fully understood, but it seems to modulate the sensibility of glutamatergic post-sinaptic receptors type N-Metil-D-Aspartate (NMDA).
Zinc was already described in the cochlea and in the cochlear nuclei. It could also be present in some others central auditory structures, because the major auditory excitatory neurotransmitter is glutamate, but it was not yet described. It is believed that the function of zinc, in the cochlea, is to protect the organ of Corti against free-radicals. In the cochlear nuclei, it seems to act regulating the neuronal systems in the dorsal cochlear nucleus.
The authors studied cochlear nuclei of Wistar rats, using the hystochemical method of Neo-Timm, in order to evidentiate zinc granules, in different levels of section, from posterior to anterior. The main features of the distribution of the ion in dorsal and ventral cochlear nuclei are presented and the neurochemical basis discussed.
